Should I capitalize the starting sentence after a greeting that ends in a comma (e.g. “Hello,”)?

Question

Should I open the starting sentence after comma in adressing "Hi," ("Hello,") with capital letter?

Hi, Xxxl, Dear Xxx L,
let me ...

vs.

Dear Xxx L,
Let me ...

In Russian it is not though it is more than frequently being goofed.

Related question:

• Comma place: “Hello Mr. Black,…” vs “Hello, Mr. Black…”

Answer 1

Since this is an informal and nonstandard mode of address (as compared to the more usual "Dear X,") I would say that rules of style are less important than for more conventional letters.

However, as far as I can tell, there is no good reason to oppose conventional style in this case. I would therefore recommend that you stick with the tried-and-true style of using a capital letter to start the letter proper:

Hi Xxxl,

Let me enquire into the origin of your weird name...

Note that there should be no comma between "Hi" and the name of the addressee.

Answer 2

Formal letters often seem to separate salutation and first line with a colon and thus continuing with a capital letter seems fit:

Dear Ms. Last:

Let me ...

Answer 3

I disagree that the comma is optional. I agree that its use has become generally accepted in informal writing, but I don't think it can be called "correct."

Most importantly, it differs entirely from the thing it's mimicking:

Dear Schnordblast,
...

Dear, in this sense is more of a title and less a greeting.

In the message, hi is addressed to Xxxl, and it therefore should get a comma to indicate that part 1 addresses part 2.

Knowing entirely that the following is unconvincing, I'll offer one more point: Think of our intonation as you would read it aloud.

Dear Schnordblast,
The years have seemed like hours since we [...]

Hi, Jim --
How goes it on the chicken farm?

In the first, the tone is even or falling throughout; in the second, it does that addressing comma thing (roughly, down on first word, up on second) along with the little stutter pause that others have referred to.

Answer 4

I was searching to see if it's common today to (incorrectly) capitalize the beginning of the sentence after the greeting (Dear Dolly,) and am surprise to discover the people answering are lost themselves.
First, there is not a comma after “Hi/hello” but before the name, unless you use a title and name: “hi, my dear sister, Yvette” or if you don’t address anyone: “Hi, this note is to inform our team that…” The only other use of a comma following “Hi” would be in creating a secondary form of addressing the same person, similar to: “Hey, you over there. Do you have the time?” in which case it would actually be written as, “Hey; you over there…” And it is not formal or correct to capitalize after "Dear Dolly," since a cap indicates one of two things: the beginning of a sentence or paragraph; or a proper noun. There is never a capitalization following a comma in any other circumstance. It's very frustrating for those of us who not only study language but love language to see people who do not really know discussing language as if they do know. I think this is a problem because there are so many who see others do something consistently and assume it is correct; or the are self-taught and misunderstood something. The world is full of exceptions to exceptions now, accommodating everyone and not wanting to correct anyone. But it's very frustrating.